Program Mail Checker is designed to verify the existence of email addresses. The main objective definition invalid email address, send mail to be rejected as a result of not existence-mail that allows to clean up your mailing list of non-existent addresses and consequently, better spend the time to link your message to the current address. The principle of Programs similar to the mail servers of ISPs: Programs sends a DNS query to determine the MX (Mail Exchange) server address, then the program tries to connect to the server and found to simulate sending the letter. The program analyzes the server response to a command to get a letter: This allows you to quickly and accurately determine the health address. Efficient processing algorithm allows answers with high precision (97%) to establish the state address, and the probability of false lock if its address is practically zero